Preparation Of Molecular Sieves Research Articles

Detoxification and Extraction of Solid and Hazardous Wastes for the Preparation of Molecular Sieves

Detoxification and Extraction of Solid and Hazardous Wastes for the Preparation of Molecular Sieves

Experimental study on the preparation of 4A molecular sieve from secondary aluminum dross

Secondary aluminum dross as a solid waste can cause great harm to environment. However, it contains rich alumina oxide which is an ideal raw material for the preparation of molecular sieve. Therefore, the optimal process was explored for the preparation of 4A molecular sieve using secondary aluminum dross as the aluminum source and an additional silicon source. The results show that the 4A molecular sieve prepared under the conditions of silicon/aluminum is 2.0, crystallization temperature of 95 °C and crystallization time of 5 h has a clear and uniform cubic crystalline structure and good calcium ion exchange capacity (389 mg CaCO3/g). It provides new direction for the high-value and resourceful utilization of secondary aluminum dross.

Preparation of Molecular Sieve Al-SBA-15 with Two Ratios Si/Al Catalyst for Use in the Transesterification Reaction of Soybean Oil

Molecular sieves have been applied to the triacylglycerides processing in the production of biodiesel through transesterification reaction. The purpose of obtain a material that has characteristics favorable to higher biodiesel conversion, this paper aims to synthesize molecular sieves SBA-15 and Al-SBA-15 on two reasons Si/Al (Si/Al= 10 and 100) evaluated in the transesterification reaction of soybean oil and investigate the potential of Si/Al ratios in the reaction over the acid each material. The catalysts were prepared by conventional hydrothermal method by varying the composition of the aluminum consequently altering the acidity of the material, since this reaction takes place in acid medium. The samples were characterized by X-Ray Diffraction (XRD), scanning electron microscopy (SEM), Spectroscopy in the infrared region by Fourier transform (FTIR). The results of the characterization of the catalysts have shown that the materials were successfully obtained, from the characterization observed. The biodiesel syntheses were conducted with soybean oil using ethyl alcohol 12: 1 relative to the oil and 5% of catalyst in the reactor with autogenous pressure. Were realized viscosity analyzes as conversion parameter of the vegetable oil into biodiesel. From the results of biodiesel viscosity was obtained a yield of 13% on average by using the Al-SBA-15. However, even not have remained within the specifications the standards of the National Petroleum, Natural Gas and Biofuels, catalysts showed efficiency compared with the SBA-15 in biodiesel synthesis.

Preparation of molecular sieve from natural pyrophyllite and characterization of its Al/Si ratio, crystal structure, and Porosity

Pyrophyllite is one abundant mineral in Indonesia which has not been optimally processed. Hence, this study further processed natural pyrophyllite to be an advanced material usable for industrial sector as a molecular sieve (MS). Natural pyrophyllitewas chosen due to its ability to filter gas or liquid selectively. The MS made from natural pyrophyllite was prepared by using a simple method, in short time and with less cost via leaching process. NaOH was varied to 10 M (MS1), 15 M (MS2), and 20 M (MS3) of molarity. Such solution was subsequently dissolved in distilled water and followed by decantation and filtration processes to obtain the deposit. Eventually, the deposit was drained to form MS powders. The BET characterization showed that the respective surface areas of MS1, MS2, and MS3 are 0.350 m2/g, 2.869 m2/g, and 1.176 m2/g with the pore sizes of 30Å, 542 Å, and 550 Å, respectively. The XRF characterization results showed that the Al/Si ratio of MS10, MS15, and MS20 are 2.4, 2.2, and 2.3, respectively. Meanwhile, the XRD investigation pointed out that the primary phase of MS10 and MS15 samples wassodalite with cubic crystal system, quartz with hexagonal crystal system, and diaspore with orthorhombic crystal system, while the MS20 phase was pure in the form of sodalite phase. Moreover, the results of FITR characterization showed that the synthesized MS has a functional group of Si-O-Si bending, Si-O-Al, Si-O, Si-O normal to the plane stretching, inner surface Al-OH deformation, Si-O-Si siloxine, H-O-H, -OH, C-H stretching, and H-O-H bending water.

Preparation of molecular sieve X from coal fly ash for the adsorption of volatile organic compounds

The coal fly ash (CFA) used in this study originated from a thermal power plant located in China Shandong (CS) province. During the experimental process, CS-CFA as raw materials was modified by acid solution (HCl) and alkaline solution (NaOH) with different concentration one after another for studying their effects on physical and chemical properties of coal fly ash. According to the results of characteristic analysis, CS-CFA modified by acid solution and then modified, respectively by 10 and 12M alkaline solution were used for the preparation of X molecular sieve. X molecular sieve was prepared at different temperature and time. The effect of temperature and time on the characteristic of X molecular sieve was discussed according to the result of adsorption experiments. Moreover, by comparison with commercial activated carbon, it has been demonstrated that synthetic X molecular sieve used for industrial production is feasible.

Preparation of Molecular Sieve from Pillaring of Kenyaite: Effects of Catalysts on Gellation of Intercalated TEOS

The effects of acid and base catalysts on the gelation of intercalated TEOS (tetraethylorthosilicate) in H-kenyaite were investigated. It was found that the base- and acid-catalyzed samples show well-ordered basal spacings and supergallery heights (base catalyst, 24.3 Å; acid catalyst, 22.1 Å). The calcination of the siloxane-intercalates yields silica-intercalated products, showing the 1 ∼ 3 Å reduction of basal spacings. The calcined samples have high surface areas in the range 533 ∼ 606 m2/g, depending on the catalyst types. As the gallery height of the calcined samples decreases, the specific surface area increases due to the development of microporosity. It was also found that the base- and acid-catalyzed samples exhibit narrow pore-size distributions near 22 and 18 Å, respectively. The pore-size distributions of the calcined samples are closely related to the gallery heights.

Preparation of molecular sieves from dense layered metal oxides

Preparation of molecular sieves from dense layered metal oxides

Analyse rapide par chromatographie en phase gazeuse : Séparation du mélange oxygène-azote-méthane-oxyde de carbone

By careful preparation of molecular sieve 5 A powder it is possible to obtain much more efficient and permeable columns than were previously available. With such columns a mixture of O 2, N 2, CH 4 and CO can be resolved in less than 15 sec.